Semiconductor device fabrication is a process used to create integrated circuits that are present in everyday electrical and electronic devices. The fabrication process is a multiple-step sequence of photolithographic and chemical processing steps during which electronic circuits are gradually created on a wafer composed of a semiconducting material.
The various processing steps fall into a number of categories including deposition, removal, patterning, and modification of electrical properties (i.e., doping). Deposition is any process that grows, coats, or otherwise transfers a material onto the wafer. Some examples of deposition processes include physical vapor deposition (PVD), chemical vapor deposition (CVD), electrochemical deposition (ECD), molecular beam epitaxy (MBE) and atomic layer deposition (ALD). Removal processes are any that remove material from the wafer either in bulk or selectively and consist primarily of etch processes, either wet etching or dry etching. Chemical-mechanical planarization (CMP) is also a removal process used between levels.
Patterning is series of processes that shape or alter the existing shape of the deposited materials and is also referred to as lithography. In one example, a wafer is coated with a chemical called a photoresist. The photoresist is exposed by exposing select portions of the wafer to short wavelength light. The unexposed regions are washed away by a developer solution. After etching or other processing, the remaining photoresist is removed.